The present invention relates to semiconductor devices having resin-covered semiconductor components on a ceramic substrate.
An example of an existing semiconductor device, having internal layer wiring formed inside its wiring boards and having the side of its external electrode portion so formed as to share the same plane as the side of each wiring board, is set forth in Japanese Application Patent Laid-Open Publication No. Hei-354355 (1992).
Examples of an existing semiconductor device, having internal layer wiring formed inside its wiring boards are set forth in Japanese Application Patent Laid-Open Publication No. Hei-163535 (1999) and Hei-304351 (1993).
An example of an existing semiconductor device, having the side of its external electrode portion formed so as to share the same plane as the side of a wiring board, is set forth in Japanese Application Patent Laid-Open Publication No. Hei-99260 (1995).
In order to achieve a reduction in the wiring resistance developed inside the internal layer wiring, through-hole wiring, wiring patterns, and external electrodes of a semiconductor device, and an improvement in the response characteristics thereof, it is becoming the common to use copper (Cu), silver (Ag), gold (Au), or the like, as the lower-resistance materials for the above-mentioned wiring conductors, and to use cold-baked type ceramic substrates that can be baked simultaneously with the foregoing wiring conductors. In such a semiconductor device, temperature changes associated with the mounting of the semiconductor device on an external wiring board, such as a motherboard, and the repetition of temperature changes associated with the starts and stops of the semiconductor device after it has been mounted on the external wiring board cause stresses due to the differences in thermal expansion coefficient between the ceramic substrate and the external wiring board. These stresses, in turn, cause a separation between the internal layer wiring and ceramic substrate of the semiconductor device, and cracking of the ceramic substrate connections with the internal layer wiring results. No prior art allows for the avoidance of these problems.
An object of the present invention is to solve the above-mentioned problems and provide a semiconductor device that incorporates preventive measures against separation between the internal layer wiring and the ceramic substrate. Another object of the invention is to provide a semiconductor device that incorporates preventive measures against the cracking of the ceramic substrate connections with the internal layer wiring. The semiconductor devices of the present invention, which are intended to attain the foregoing objects, comprise a ceramic substrate provided with the first and second principal planes, a wiring pattern formed on said first principal plane and having mounted semiconductor components, an external electrode portion formed on said second principal plane and connected to an external circuit, internal layer wiring formed inside said ceramic substrate to electrically connect said wiring pattern and said external electrode portion via through-hole wiring, semiconductor components connected to said wiring pattern, and a resin layer for covering said first principal plane and said semiconductor components; wherein said internal layer wiring is characterized in that it is formed internally with respect to the side of said ceramic substrate with a clearance of at least 0.05 mm.
Also, it is preferable that the side of said external electrode portion be formed on essentially the same plane as the side of said ceramic substrate.
The semiconductor components here refer to semiconductor device base substances, such as integrated circuit (IC) element base substances and field-effect transistor (FET) element base substances, and chip components such as passive elements represented by chip resistors and capacitors. Also, the wiring boards used for the semiconductor devices of the present invention include a ceramic substrate and a board having a wiring pattern, an external electrode portion, through-hole wiring, and internal layer wiring, all of which are formed on or in the ceramic substrate. In addition, the wiring board composite body is a board assembly consisting of multiple wiring boards.